The present invention relates to a vehicular headlamp including a light projection unit which employs a projection lens to project and direct light produced by a light source and reflected by a substantially ellipsoidal reflector to thereby form a low beam. More particularly, the invention relates to a vehicular headlamp in which a second headlamp main body consisting of the light projection unit forms a low beam from a single beam of the light projection unit and the beam of the first headlamp main body is combined with the beam of the second headlamp main body to thereby form a high beam.
In FIG. 15 there is shown a conventional headlamp of the above-mentioned type in which a parabolic reflector unit a forming a first headlamp main body, a light projection unit b forming a second headlamp, and a side lamp unit c are mounted together between a lamp body 1 and a front lens 2. According to this structure, a low beam (indicated by P1 in FIG. 16) is formed by only the light projection unit b, while a high beam (which includes the areas of P.sub.1 and P.sub.2 in FIG. 16) is formed by light reflected from the parabolic reflector unit a and the light projection unit b.
The light projection unit b is of an integral structure in which a light source 4 is disposed at a first focal point of a substantially ellipsoidal reflector 3, a projection lens 6 is disposed in front of the reflector 3, and a shade 5 is disposed at a focal point of the projection lens 3 for intercepting a part of the light produced by the source 4 to thereby form a low beam. These components are integrated into one unit.
The light projection unit b is able to provide a larger quantity of light and is more compact in size than the headlamp main body a of a parabolic reflector unit type which reflects the light of a light source 7 with a parabolic reflector 8 and distributes and controls the light using light distribution and control steps 2a formed on the front lens 2. For this reason, light projection units have been recently used more frequently.
In FIG. 16, reference numeral 9 designates an extension reflector which intercepts light to thereby prevent the light from leaking from respective areas, that is, a headlamp area and a side lamp area, and covers gaps in the periphery of the first and second headlamp main bodies a and b to thereby make the whole interior of the lap body have a mirrored appearance when viewed from the outside to thus make it look more attractive.
However, in the conventional headlamp, the near portion (the area close to the vehicle) of the high beam, which is produced by combining together the beams of the parabolic reflector unit a and light projection unit b, generally receives a disproportionately great share of the total light output so that distant areas (areas shown by oblique lines in FIG. 16) of the high beam are relatively darker, thereby impairing the illuminating pattern of the headlamp.